The purpose of this study is to investigate the antimicrobial susceptibility of Strep. mutans. Strains examined will represent the different serotypes and isolates from different geographic locations. Oxoid multidiscs are currently being used to serve as a rapid means of screening a relatively large number of antimicrobials in order to select 8 to 12 for determination of minimal inhibitory concentrations (M.I.C) by a broth microdilution procedure.